When generating an image with the depth, an image generation apparatus generates an image with a clear contour relating to an object which is in a focus region of a camera, and generates an image with a blurred contour relating to an object which is in an out of a focus region of a camera with respect to the depth direction of an image. In this manner, the image generation apparatus generates an image in which a perspective sensation is expressed to be close to a real world.
PTL 1 discloses a parallax estimating method of estimating parallax which discontinuously changes along an object contour line. In the parallax estimating method, initial parallax of two images and a reliability evaluation value of an initial parallax are calculated, and parallax in a region in which the reliability of the initial parallax is low is set to be smoothly connected to the peripheral parallax, and is determined to be changed along the object contour line.
PTL 2 discloses an image generation system which generates an image which is focused like a visual field image of a real world. In the image generation system, a focused image is generated by setting an α value corresponding to a depth value of each pixel of the original image, and by compositing the original image and a blurred image corresponding to the original image based on the α value which is set in each pixel.
In addition, PTL 3 discloses an image processing program which generates a focused image based on a distance from a view point. The image processing program includes a step of setting an α value of each pixel based on a depth value of each pixel of a standard image, and a step of increasing an α value which is set to a pixel of which an α value is small between two pixels which are close to each other. Therefore, the image processing program generates a focused image by compositing a standard image and a blurred image corresponding to the standard image based on the α value which is set in each pixel after the processing by the increasing step.